The present disclosure relates to a navigation system capable of estimating a time period required for a movable body to move between any given points. The navigation system is also capable of estimating a time period required for movement along a route different from that of the movable body.
As is generally known, navigation systems mounted on vehicles search for a route from a place of departure to a destination and provide guidance on the found route to users. However, conventionally, when a vehicle leaves an initial route guided by a navigation system and arrives at a destination via an alternative route, even if the user wants to compare required time periods when the vehicle leaves the initial route and arrives at the destination and when the vehicle arrives at the destination without leaving the initial route, the user has no way to make such a comparison.
In contrast, a system has been proposed that transmits an agent program to another vehicle traveling along a route different from the route of the host vehicle to set the other vehicle as a virtual vehicle (e.g., see Japanese Laid-Open Patent Publication No. 2004-245609). In this system, the virtual vehicle, which has received the agent program, transmits a traveling result to the vehicle that is the transmission source of the agent program though a function of the agent program. When the virtual vehicle, which has received the agent program, leaves the alternative route it is traveling, the virtual vehicle transfers the agent program to a third vehicle that is traveling the route. Thus, the third vehicle, which has received the agent program, is newly set as a virtual vehicle and transmits the traveling result to the host vehicle, which is the transmission source of the agent program.
According to the above-described system, even if a vehicle that is a virtual vehicle leaves the route to be compared, another vehicle traveling the route is set as a virtual vehicle. It is thus possible to calculate a required time period that reflects changing factors such as congestion and traffic control.
However, the vehicle that has received the agent program does not always display the same traveling performance as that of the host vehicle. Therefore, even when the time period required by the virtual vehicle is calculated using the traveling result of the vehicle that has received the agent program, it is difficult to bring the required time period calculated in this way closer to the required time period when the host vehicle actually travels along the alternative route. Such a problem is not limited to navigation systems mounted on vehicles or other movable bodies, but is generally common to navigation systems or the like incorporated in portable information terminals, for example.
It is an objective of the present invention to provide a navigation system capable of obtaining, even for a route along which a movable body does not actually move, results similar to results that would be obtained if the movable body actually moved along the route.